Continuous casting machine

ABSTRACT

A continuous casting machine is provided with a casting position and at least one preparation position. At least two molds are provided, with each mold connected to a section of a roller apron to form a mold unit which is so mounted that it is movable as a unit between the casting position and a preparation position and vice versa. While metal is being cast through one mold unit at the casting position, the other mold unit at a preparation position may be prepared for use in the next casting operation, including insertion of a dummy bar. When the mold unit is at the casting position, the movable section of the roller apron is aligned with a fixed section of the roller apron, so that the two sections form a continuous guideway for the casting leading to withdrawal rollers.

United States Patent 1 Burkhardt et al.

[ Nov. 20, 1973 CONTINUOUS CASTING MACHINE [73] Assignees: Concast AG,Zurich, Switzerland; Concast Incorporated, New York, NY.

[ Filed: July 20, 1971 1211 Appl. N0.: 164,404

[30] Foreign Application Priority Data 164/282, 283, 283 R, 283 S, 283M, 283 MS, 283 MT; 193/35 R, 35 A, 35 SS, 35 C, 35 TE, 35 MD, 35 .l, 35G, 35 B, 35 S; 266/13 [56] References Cited UNITED STATES PATENTS3,495,651 2/1970 Rokop 164/282 X 3,167,829 2/1965 Hess 164/282 3,446,2705/1969 Michelson. 164/282 3,346,036 10/1967 Tarmann.... 164/282 X3,590,908 7/1971 Reinfeld 164/282 2,920,359 1/1960 Easton 164/274 X3,273,208 9/1966 Greenberger.. 164/274 X 3,620,285 11/1971 Olsson164/282 3,672,438 9/1970 Hofmann 164/282 Primary Examiner-J. SpencerOverholser Assistant Examiner-John S. Brown Att0meyNichol M. Sandoe etal.

[57 ABSTRACT A continuous casting machine is provided with a castingposition and at least one preparation position. At least two molds areprovided, with each mold connected to a section of a roller apron toform a mold unit which is so mounted that it is movable as a unitbetween the casting position and a preparation position and vice versa.While metal is being cast through one mold unit at the casting position,the other mold unit at a preparation position may be prepared for use inthe next casting operation, including insertion of a dummy bar. When themold unit is at the casting position, the movable section of the rollerapron is aligned with a fixed section of the roller apron, so that thetwo sections form a continuous guideway for the casting leading towithdrawal rollers.

19 Claims, 9 Drawing figures PAIENIEUunvzo um 3.773.103 sum 10F 4 30FIG.2

PATENTEDNDV 20 ms 3773.103 SHEET REF 4 FIG? FIGS

CONTINUOUS CASTING MACHINE The invention relates to a continuous castingmachine for steel comprising at least two oscillable molds, a tundishassociated with each mold for pouring steel into the mold when the moldis in casting position, a segmented roller apron comprising a movablesection and a fixed section, each of said sections being equipped withsecondary cooling means, strand with drawing means, a dummy bar and adummy bar handling mechanism. Each mold, together with a movable sectionof the roller apron which directly adjoins the mold forms a mold unitwhich is movable into and removable from the casting position. When themold unit is in casting position the movable section of the roller apronis aligned with the fixed section of the roller apron and forms acontinuous guideway for the casting leading to the strand withdrawingmeans.

The efficient operation of a continuous casting machine when castingsteel requires complete coordination between the tapping cycles of thehot-metal production units and the casting cycles of the continuouscasting machine. A complete casting cycle comprises the actual pouringtime of one continuous strand and the preparation time required toprepare the machine for casting the next strand. During the preparationtime the end of the first strand must be fully withdrawn from themachine, a dummy bar must be introduced into the roller apron, and thedummy bar head must be moved into and sealed in the mold. Thispreparation time, which requires at least 30 minutes in most steelcasting machines, adversely affects the productive capacity of themachine. This capacity may be further reduced by planned interruptions,such as to make changes in the mold and roller apron to change the crosssection of the strand, or by changes in the type of the steel to becast, as well as by unforeseen interruptions, such as metal breakouts.

It is known to increase the capacity of a continuous casting machine byusing what is known as continuous continuous casting in which a seriesof successive ladle charges are poured without interruption, becausepreparation time will only be required before the casting of the firstladle. However, continuous continuous casting is only possible when thetapping times ofthe hot-metal producing furnaces are exactlysynchronized with the casting rate of the continuous casting machine.Events which disturb this synchronism can never be completelyeliminated. Moreoever, continuous continuous casting is usuallypracticed only when the type of steel and the cross section of thestrand remain unchanged. Metal breakouts, damaged refractory parts orother difficulties may necessitate the stopping of the continuouscontinuous casting process. Such problems limit the usefulness ofcontinuous continuous casting, particularly in steel works which producea wide variety of products.

It has been proposed to reduce the preparation time elapsing between thecompletion of one strand and the beginning of the next, by introducing adummy bar head into the mold or into a spare mold, locking it in place,and then preparing the head for beginning the next cast while theprevious strand is still in the roller apron and is in the course ofbeing withdrawn. As soon as the point of entry of the dummy bar into theroller apron has been cleared by the withdrawing strand, the dummy barmay be introduced into the roller apron and advanced and connected tothe head which is already in the mold prepared for casting, so that anew casting can begin immediately. Some reduction in preparation timecan thus be acieved, but the withdrawal of the previous strand, theintroduction of the dummy bar, the change-over to a different castingsection and other operating difficulties nevertheless still causeconsiderable losses of time.

It has also been proposed to combine the mold, the mold table and a partof the roller apron which is adjacent the mold into one unit which canbe removed as a unit from the casting position and a replacement unitcan be substituted by a crane. This procedure reduces the preparationtime somewhat, particularly when the casting cross-section has to bechanged or when operating trouble such as a breakout occurs. However,considerable time is still required for introducing the dummy bar intothe unit and for sealing the dummy bar head in the mold.

In yet another known continuous casting machine the mold is sealed witha mold plug that is substantially shorter than the distance between themold and the first driven roller of the roller apron. This mold plug canbe moved downward in the roller apron by conveyor chains which arelocated on opposite sides of the roller apron until it reaches the firstdriven roller. In a position located to one side of the normal castingposition the mold plug is introduced into a mold and secured to it bylocating means. The mold is then transferred into normal castingposition and the mold plug is inserted into the roller apron and coupledto the chain conveyor. Although in this machine the mold plug isintroduced into the mold away from the normal casting position, thefollowing operations which increase the preparation time of the machinemust still be performed after the mold has been transferred into castingposition: (a) The mold plug must be introduced into the roller apron andcoupled to the conveyor. (b) The locating means of the plug must beremoved and it must be manipulated by the conveyor into the desiredposition in the mold and then sealed. (c) In continuous casting machineshaving guide means on all four sides of the casting, the guide means ontwo opposite sides must be adjusted to the new width and must be alignedto the position of the mold. (d) The pouring of metal can start onlywhen the mold is in casting position. (e) In the case of operatingdifficulties, particularly in the event of a metal breakout, the samerepair time is required as with a conventional plant.

It is an object of the present invention to provide a continuous castingmachine in which the preparation time required between the end of onecast and the beginning of the next is substantially less than thatrequired by prior methods or procedures, so that a high productivecapacity of the machine is obtained.

This object is accomplished by providing two separate mold units, eachunit comprising a mold and a movable section of the roller apron whichdirectly adjoins the mold, with each of said roller apron segmentshaving at least one driven roller therein. One mold unit is in castingposition, while the other mold unit is in preparation position. The unitwhich is in preparation position cooperates with a dummy bar handlingmeans for the insertion of a short dummy bar into the unit.

The invention permits the reduction of the preparation time to 5 to 10minutes, depending on the size of the machine. The mold cross-sectionand/or the type of steel of consecutive castings can be changed withoutincreasing the preparation time. In the event of a breakout of metalwhich usually occurs in the zone of the roller apron immediatelyadjacent the mold it is often possible to resume casting after a veryshort time by replacing the damaged mold unit by the other unit which isin the preparation position. The duration of a shut-down due to suchcauses can thus be minimized.

Drive means are provided for inserting a dummy bar into the mold unitwhile it is in the preparation position. However, separate drive meansfor completely inserting the dummy bar into the mold unit areunnecessary if, according to another feature of the invention, means areprovided for driving the driven roller of the mold unit whilst the unitis in the preparation position.

To avoid having to fill the mold with coolant and to vent it after ithas been transferred from the preparation position into the castingposition, a further feature of the present invention provides the supplyand return pipes for the coolant of the mold with valves to prevent thecoolant from draining.

It is also possible to introduce the dummy bar into the mold unitthrough the mold from above when the mold unit is in the preparationposition.

However, in order to clear the casting platform of apparatus for thehandling of a dummy bar and also in order to reduce the length of thefeed path of the dummy bar to a minimum, it is proposed according toanother preferred feature of the invention to introduce the dummy barinto the mold unit from below through the section of the roller apronattached thereto. Preferably the dummy bar handling device is equippedwith a roller table which may be tilted to cooperate with the section ofthe roller apron which is a part of the mold unit.

Moreover, for the purpose of axially aligning the movable and fixedsections of the roller apron with allowance for thermal expansion, themovable section of the roller apron may be tiltably mounted at its endadjacent the mold, while the other end bears against the structure ofthe machine when it is in casting position.

According to one form of the invention, the length of the castingplatform may be shortened by mounting the tundishes to be swivelledabout a kingpost located on the operating side of the mold.

It may often be useful to provide an emergency cutting station betweenthe movable section and the fixed section of the roller apron so that inthe event of a breakout, the damaged casting may be cut up and removedpiece by piece, so that the casting operation can be resumed within afew minutes.

The mold unit can be lifted into the preparation position and then backagain into the casting position by a crane. However, particularly in thecase of multiple strand machines in which the casting ladies are broughtup by a crane, an interruption of the casting process and an increase inthe loss or productive time cannot be avoided. According to the presentinvention it is therefore proposed to mount at least one mold unit onhorizontal transporting means. Conveniently, one or more preparationpositions may then be located laterally of the casting position and thetransporting means may be cars that can be moved laterally.

In order to avoid the need of mechanical and/or hydraulic couplings forthe several systems of the unit, for instance for mold oscillation, fordriving the oilhydraulic motors of the driven rollers and for pressingthe driven rollers against the strand, for lubricating the mold and soforth, another feature of the invention proposes to provide the unitwith at least one emergency generator.

After use in starting a casting operation, the dummy bar can be quicklyand conveniently returned to the one or the other of the two preparationpositions which are located laterally of the casting position. For thispurpose means are provided for handling the dummy bar including meansfor the transverse and longitudinal transportation of the dummy bar, thetransverse transporting means interconnecting with the longitudinaltransporting means located on each side of and above the strand guidemeans.

When the cross section of the casting is to be changed, it may also benecessary to change the dummy bar head and/or the dummy bar. Accordingto yet another feature of the present invention this can be easily andconveniently done if the transverse transporting means comprise a rollertable mounted on a car, traveling on tracks which extend to an areawhere dummy bars and dummy bar heads are stored.

For improving the freedom of movement of the casting platform, a covermay be attached to the mold unit transport car to move over thepreparation position when the car moves the mold unit to its castingposition.

The cost of the dummy bar handling means can be reduced substantiallyif, according to a further feature of the invention, the two mold unitsshare a common preparation position. Such an arrangement may beparticularly space-saving if the mold unit transport car is a turntable.

In order to save even more space it is advantageous that the turntableand the swivelling tundishes have a common pivot post.

It may be desirable for spcial reasons, such as a further reduction ofthe preparation time, and/or for fixing the dummy bar in the mold, tostart pouring the metal into the mold when the mold unit is still in thepreparation position, or when it is moving into casting position. Forthis, the tundish and the mold unit must be aligned and must move withthe same speed.

For a twin-strand casting machine a particularly com pact andtechnically superior arrangement results when both units which arenecessary for each strand are mounted on a common turntable, and bylocating the two turntables adjacent to each other.

Preferred embodiments of the present invention will be hereinafterdescribed with reference to the accompanying schematic drawings inwhich:

FIG. 1 is a section of a continuous casting machine taken on the line II of FIG. 3.

FIG. 2 is a secton taken on the line II II of FIG. 3.

FIG. 3 is a plan view of the continuous casting machine.

FIG. 4 is a plan view of another embodiment of a continuous castingmachine according to the present invention.

FIG. 5 is a section taken on the line V V of FIG. 4.

FIG. 6 is a plan view of yet another embodiment of a continuous castingmachine according to the present invention.

FIG. 7 is a section taken on the line VII VII of FIG.

FIG. 8 is a section taken on the line VIII VIII of FIG. 6, and

FIG. 9 is a section of the inlet and outlet pipes for mold coolant formold units which are arranged on a turntable. 7

Referring to H6. 1, a ladle l carrying molten steel is located above andin position to pour steel into tundish 2. The tundish is positioned topour into an oscillable mold 3 in which the cast strand begins to formand from which it moves into a secondary cooling zone wherein it issupported and guided by a roller apron comprising a movable section 8and a fixed section 9. The section 8 of the roller apron and the mold 3form a mold unit that is removable as a unit from the casting positionshown. The fixed section 9 of the roller apron and strand withdrawingmeans 7 are aligned with the mold unit 10 when it is in casting position4. The withdrawing means 7 also preferably functions to straighten thestrand. The withdrawing means 7 may be followed by a cutting station 6.Both movable section 8 and fixed section 9 of the roller apron arefitted with customary secondary cooling equipment (not shown) for directapplication of coolant to the strand. The mold units 10 are providedwith means for holding and feeding the dummy bar. For this purposesection 8 of the roller apron is equipped with at least one drivenroller 11 so that the dummy bar can be moved or locked in the unit 10.If desired several such rollers 11 and 12 in the unit 10 are drivenrollers and hydraulic means may be provided for pressing them againstthe strand or dummy bar.

In the case of dummy bars which are themselves provided with means forholding them inside the unit 10, or for horizontal machines, no specialholding means are needed in the unit 10.

Beyond the roller apron is located a dummy bar tilting table 15 which ispositioned to intercept and detach a short dummy bar 18 from the strand.After detaching the dummy bar from the strand, the table is swung to ahorizontal position from which the dummy bar may be moved onto atransverse transporting car 17. The dummy bar 18 may be as long orshorter than the segment 8.

As shown in FIGS. 1, 2 and 3, the mold unit 10 is mounted on horizontaltraversing equipment comprising a car 30 which is movable on wheels 35laterally across the longitudinal axis of the strand.

FIG. 1 shows the casting position 4 of the machine with the ladle l andthe tundish 2 in position to pour metal into the mold 3 from which thepartially solidified strand is delivered to the movable section 8 of theroller apron through which it proceeds to the fixed section 9 and thenceto the withdrawing means 7. The dummy bar 18 has been deposited on thecar 17. While casting is proceeding at the casting position, anothermold unit and tundish may be prepared for casting as shown in FIG. 2.

in F105. 2 and 3 a second mold 3' and second movable section 8' of theroller apron forming a second mold unit 10' which together with a secondtundish 2' is carried on car 30 located in a preparation position 5.While in this position, the dummy bar 18 may be moved from the car 17further along the conveyor 16 to a position adjacent the section 8' ofthe roller apron of unit 10'. This conveyor 16 comprises a transversetransporting car 17, a fixed roller table 20 and a tiltable roller table22 located below section 8 of the roller apron. A power cylinder unit 24is provided to tilt the roller table 22 about a pivot 25 to bring itinto alignment with section 8' of the roller apron. The tiltable rollertable 22 is provided with means, such as a driven roll 26, for feedingthe dummy bar into the section 8. The movement of the dummy bar into thesection 8' may be assisted by the rollers 11 and 12 which can be driveneven when the mold unit 10 is in the preparation position.

While in the preparation position of HG. 2, the tundish 2 may beprepared to receive metal by heating it by a gas burner.

FM}. 3 shows the lateral disposition of the two preparation positions 5,5' in relation to the casting position 4. For greater clarity the ladlel is not shown in FIG. 3. Rails 31 are mounted on the platforms 33 ofthe cars 30 and 30' in order to facilitate moving the tundishes 2, 2from the preheating stations 32 respectively 32' to the castingposition.

The car 17 for the transverse transport of the dummy bar runs on rails27 and can transfer the dummy bar from the tilting table 15 to either ofthe roller tables 20, 20'. The car 17 also services a stockpile 28 ofdummy bars and dummy bar heads of different cross sections.

Platforms 33 of the cars 30, 30 are preferably long enough to projectbeyond the end of the casting platform when in the preparation positionand to cover the preparation positions 5, 5' when the cars are moved tocasting position so that no opening will be formed in the floor.

The operation of the machine may be described with reference to asituation in which, while casting a particular cross section at castingposition 4, it is desired to prepare for changing the cross section ofthe next casting. The mold unit 10' in the preparation position 5 isalready being adjusted to the new cross section whilst casting continuesin position 4. The transverse car 17 then picks up a dummy bar 18 of theproper configuration from the stockpiling area 28 and conveys it to theroller table 20 along which it travels to the tiltable roller table 22.As soon as the mold 3' and the segment 8' of the roller apron have beenadjusted to the new cross section, the roller table 22 is then tilteduntil the head of the dummy bar 18 is correctly aligned with the section8 of the roller apron. The driven roller 26 then drives the dummy bar 18into engagement with the driven rollers 11 and 12 which may be providedwith oil-hydraulic motors and hydraulic devices which press them againstthe strand and cause them to feed the strand. Such devices may beautomatically coupled to pressure-generating elements when they reachthe casting position 4 or the preparation position 5. The rollers 11 and12 advance the dummy bar 18 until its head enters the mold. Then thehydraulic pressure device is activated to tighten the roller pairs tohold the dummy bar in this position. The tiltable roller table 22 isthen restored to horizontal position. Meanwhile the dummy bar head maybe sealed inside the mold. When this has been completed, the mold unit10' is ready for casting and can be moved into casting position whenneeded.

Shortly before the pouring of metal into mold 3 ceases, the preheatedtundish 2' is moved to a location above the mold 3' and is aligned withthe mold. As soon as the end of the strand has left section 8 of theroller apron, the mold unit 10, including the tundish 2, is moved by thecar 30 into the preparation position 5. Then the car 30 moves thetundish 2' and the mold unit 10' into casting position 4 so that thesection 8' of the roller apron is aligned with the fixed section 9 ofthe roller apron. Thereupon pouring of metal may begin. Shortlythereafter the hydraulic locking of the dummy bar in the segment 8' isreleased and the roller pairs ll and R2 are driven to start withdrawingthe dummy bar and the partially solidified strand. After the leading endof the dummy bar has passed the withdrawing unit 7, the dummy bar iswithdrawn by a chain or cable connected to a winch on the tilting table15. As the dummy bar head reaches the table 15, it is tilted into ahorizontal position which automatically detaches the dummy bar head fromthe strand. The dummy bar 18 is then pushed onto the car 17 and conveyedlaterally to the roller table 20 along which it is conveyed to thetilting table 22'. Thereafter the dummy bar is moved into the mold unitill which is in the preparation position and is prepared for the nextcasting. Alternatively, the unit may be fitted with a different dummybar before the dummy bar from the preceeding casting has becomeavailable.

FIG. 3 illustrates another embodiment of a continuous casting machine inwhich the mold unit it) is in casting position 4 and a mold unit 10' isin the preparation position 5. Mold units Ml and ill are both mounted ona common car dl. Tundishes ill and d3 are mounted for swiveiling on akingpin 42 located adjacent the operating side of the mold. The tundish43 is located above the mold 3 in pouring position, and the tundish 43'is located at a preheating station which is equipped with a gas burner45. The second preparation position 5 may be covered by a foldingshutter 46. This shutter 46 is attached to the car 41 and is folded orunfolded by the movement of the car.

In FIG. 5 movable section 8 of the roller apron can be tilted about apivot Sl which is located adjacent the end which faces the mold 3, whilethe opposite end of the section 8 is supported by an abutment 52 whichbears against the structure 53 when the section is in casting position.This tiltable mounting permits adjustment to compensate for inaccuraciesin the roller apron alignment which may be due to tolerances in thetransverse moving system and to unequal thermal expansion of the tworoller apron sections S and 1G.

in order to enable the mold unit 10 to be moved out of the castingposition 4 when a breakout of metal has occurred, and also in order toenable the casting to be withdrawn from the other section 9 of theroller apron, an emergency torch cutter 55 is provided between the twosections 8 and 9. if the roller spacing between the segments 3 and Q isnarrow, additional space for a cutter can be created by lifting orlowering the mold unit it) or the car at.

The dummy bar handling means comprises hoisting means 56 carrying amagnet 57 which lifts the dummy bar off the tilting table and lowers itonto a roller table 5%.

FIG. 6 shows a twin-strand machine in which each of the two turntablesfill and 60 carries a mold unit it) in casting position and a mold unitlltl in preparation position. In such an arrangement casting may proceedin one or both of the units 10 depending on the requiremerits andcircumstances. The positions 611 and 63' are provided as preparationpositions for the two mold units 10. Such a machine may be equipped witha common tundish (not shown) for both mold units Ml, or may have, asindicated in the drawing, two separate tundishes 65 and 65' for eachstrand. In a particularly useful arrangement, the kingpin 62 forswivelling the tundishes 65 and 65 serves also as the axis of rotationfor the turntable 60. With such an arrangement it is possible to centerthe tundish 55 with respect to the mold unit 10 while it is still in thepreparation position 611, and then to swing the turntable, together withthe tundish 65'into the casting position If desired, the filling of themold with molten steel may start while the mold is still in thepreparation position 61 and the pouring can continue while the turntableand the tundish swing into casting position. If the dummy bar issuitably short and the driven rollers 11 and 12 are appropriatelylocated even the withdrawal of the casting may already start in thepreparation position.

FIG. 7 is a section through the mold unit 10 in casting position 4, withthe movable section 8 of the roller apron aligned with the fixed section9. In this embodi ment of the invention the section 8 is equipped withcooling plates 70, guide rollers '73 and driven rollers 11 and H2.

The turntable 60 may be equipped with electrical drive means to generatethe mold oscillation, and may also be equipped with hydraulic pumps 72for the oilhydraulic motors and the hydraulic pressure means for thedriven rollers ll and 12. Another drive means (not shown) may beprovided for supplying oil for mold lubrication.

FIG. 8 is a section through a mold unit 10' in preparation position 61,with the movable section 8' of the roller apron aligned with a tiltedroller table 81 similar to the roller table 22 of FIG. 2. The dummy barhandling means comprises a hoisting means 56 which is adapted to turnthe dummy bar horizontally through an angle of 180 before depositing iton a roller table 82 to bring the dummy bar head 83 into the correctposition for entry into the section 8'.

FIG. 9 shows the mold 3 in casting position and the mold 3' inpreparation position. The inlet and outlet pipes 1 and 91 for the moldcoolant are connected to a rotatable ring 92 which is concentric withthe turnta ble as and rotates with it. This ring 2 and the coolantsupply pipes 93 in the hub 94 constitute a rotary stop valve 95 toprevent loss of coolant. Depending on the position of the turntable 60and therefore of the ring 92 the inlet and outlet pipes 93 and 91' areeither coupled to or disconnected from the supply pipes 93.

We claim as our invention:

l. A continuous casting machine for steel having a casting position andat least one preparation position spaced laterally from said castingposition, said machine comprising at least two movable mold units, eachof said mold units consisting ofa mold and a section of a roller apronconnected thereto and movable therewith, a fixed section ofa rollerapron located below and aligned with said casting position, means fortransporting said mold units from said casting position to saidpreparation position and from said preparation position to said castingposition with said movable section of the roller apron aligned with saidfixed section thereof when said mold unit is in casting position, meansfor driving at least one roller of each of said movable sec tions of theroller apron, a dummy bar, dummy bar conveyor means spaced laterallyfrom said casting position and aligned with said preparation position toconvey said dummy bar to the movable mold unit at the preparationposition, and means for feeding said dummy bar from said conveyor meansinto engagement with the driven roller of the roller apron of saidmovable mold unit.

2. A continuous casting machine according to claim 1 in which said meansfor driving at least one roller of each of said movable sections of theroller apron is operable at the preparation position.

3. A continuous casting machine according to claim 1 including inlet andoutlet pipes for coolant for the mold, and valve means to control theflow of coolant.

4. A continuous casting machine according to claim 1 in which said dummybar conveyor includes a tiltable table adapted to be aligned with themovable section of the roller apron.

5. A continuous casting machine according to claim 1 in which when themold unit is in casting position the end of the movable section of theroller apron which is adjacent the mold is tiltably mounted and theother end bears against a fixed abutment.

6. A continuous casting machine according to claim 1 including at leasttwo tundishes, a kingpin located on the operating side of the mold, saidtundishes being mounted for swivelling on said kingpin.

7. A continuous casting machine according to claim 1 including emergencymeans for cutting the cast strand at a point between said fixed and saidmovable sections of said roller apron.

8. A continuous casting machine according to claim 1 in which said moldunit includes at least one power generator.

9. A continuous casting machine according to claim 1 in which said meansfor transporting said mold units is mounted to move horizontally to andfrom a preparation position located laterally of said casting position.

10. A continuous casting machine according to claim 9 in which saidtransporting means comprises a car.

11. A continuous casting machine according to claim 1 in which saiddummy bar conveyor means is located on either side of and above the caststrand and includes means for transporting said dummy bar laterally andlongitudinally.

12. A continuous casting machine according to claim 10 including aplatform connected to said car which moves with the car and covers thepreparation position when the car moves to the casting position.

13. A continuous casting machine according to claim 1 in which saidmeans for transporting said mold units comprises a turntable.

14. A continuous casting machine according to claim 13 in which saidturntable transports said mold units to a common preparation position.

15. A continuous casting machine according to claim 13 including twotundishes located above said turntable, and means for mounting saidtundishes to swivel on the same axis as that on which said turntableturns.

16. A continuous casting machine according to claim 12 including atundish mounted on said platform and moving with said platform.

17. A continuous casting machine according to claim 13 in which two moldunits are mounted on each of two adjacent turntables.

18. A continuous casting machine according to claim 11 in which saidlateral transporting means comprises a roller table mounted on a car.

19. A continuous casting machine according to claim 15 in which saidtundishes turn with said turntable as said turntable turns.

1. A continuous casting machine for steel having a casting position andat least one preparation position spaced laterally from said castingposition, said machine comprising at least two movable mold units, eachof said mold units consisting of a mold and a section of a roller apronconnected thereto and movable therewith, a fixed section of a rollerapron located below and aligned with said casting position, means fortransporting said mold units from said casting position to saidpreparation position and from said preparation position to said castingposition with said movable section of the roller apron aligned with saidfixed section thereof when said mold unit is in casting position, meansfor driving at least one roller of each of said movable sections of theroller apron, a dummy bar, dummy bar conveyor means spaced laterallyfrom said casting position and aligned with said preparation position toconvey said dummy bar to the movable mold unit at the preparationposition, and means for feeding said dummy bar from said conveyor meansinto engagement with the driven roller of the roller apron of saidmovable mold unit.
 2. A continuous casting machine according to claim 1in which said means for driving at least one roller of each of saidmovable sections of the roller apron is operable at the preparationposition.
 3. A continuous casting machine according to claim 1 includinginlet and outlet pipes for coolant for the mold, and valve means tocontrol the flow of coolant.
 4. A continuous casting machine accordingto claim 1 in which said dummy bar conveyor includes a tiltable tableadapted to be aligned with the movable section of the roller apron.
 5. Acontinuous casting machine according to claim 1 in which when the moldunit is in casting position the end of the movable section of the rollerapron which is adjacent the mold is tiltably mounted and the other endbears against a fixed abutment.
 6. A continuous casting machineaccording to claim 1 including at least two tundishes, a kingpin locatedon the operating side of the mold, said tundishes being mounted forswivelling on said kingpin.
 7. A continuous casting machine according toclaim 1 including emergency means for cutting the cast strand at a pointbetween said fixed and said movable sections of said roller apron.
 8. Acontinuous casting machine according to claim 1 in which said mold unitincludes at least one power generator.
 9. A continuous casting machineaccording to claim 1 in which said means for transporting said moldunits is mounted to move horizontally to and from a preparation positionlocated laterally of said casting position.
 10. A continuous castingmachine according to claim 9 in which said transporting means comprisesa car.
 11. A continuous casting machine according to claim 1 in whichsaid dummy bar conveyor means is located on either side of and above thecast strand and includes means for transporting said dummy bar laterallyand longitudinally.
 12. A continuous casting machine according to claim10 including a platform connected to said car which moves with the carand covers the preparation position when the car moves to the castingposition.
 13. A continuous casting machine according to claim 1 in whichsaid means for transporting said mold units comprises a turntable.
 14. Acontinuous casting machine according to claim 13 in which said turntabletransports said mold units to a common preparation position.
 15. Acontinuous casting machine According to claim 13 including two tundisheslocated above said turntable, and means for mounting said tundishes toswivel on the same axis as that on which said turntable turns.
 16. Acontinuous casting machine according to claim 12 including a tundishmounted on said platform and moving with said platform.
 17. A continuouscasting machine according to claim 13 in which two mold units aremounted on each of two adjacent turntables.
 18. A continuous castingmachine according to claim 11 in which said lateral transporting meanscomprises a roller table mounted on a car.
 19. A continuous castingmachine according to claim 15 in which said tundishes turn with saidturntable as said turntable turns.